The present invention relates to minimizing the generation of particles in ultra pure liquids. In particular, the present invention relates to minimizing the generation of particles in ultra pure liquids during filling, dispensing, and transport of containers.
Numerous industries require that the number and size of particles in ultra pure liquids be controlled to ensure purity. In particular, because ultra pure liquids are used in many aspects of the microelectronic manufacturing process, semiconductor manufacturers have established strict particle concentration specifications for process chemicals and chemical-handling equipment. These specifications continue to become more stringent as manufacturing processes improve. Such specifications are needed, since if the fluids used during the manufacturing process contain high levels of particles, then the particles may be deposited on solid surfaces. This can in turn render the product deficient or even useless for its intended purpose.
A general philosophy behind the specifications is that if the fluid is clean, and the fluid handling component is also clean, the fluid passing through the component will remain clean. Alternatively, if a fluid container is clean, and the container is being filled with clean fluid, the fluid will remain clean during the filling process. A clean fluid in a clean container should still be clean upon delivery to the customer. Fluid handling components fresh from the manufacturing operation are often cleaned prior to packaging, and inherent in the cleaning operation is the assumption that the cleaning system itself does not contaminate the cleaning liquid. In contrast, it is also generally recognized that certain fluid handling components, like pumps, will continuously shed particles into the fluid that the pump is delivering.
However, it is not generally recognized that particles can appear in fluids to a greater or lesser degree depending upon the manner in which the fluid is passed through a component or is delivered to a container. For example, it has been discovered that if a clean container is partially filled with clean water, capped, and shaken vigorously, the particle concentration in the water will increase dramatically. New steps are required to ensure that particle concentrations in liquids are low enough to meet the stringent industrial specifications.
Thus, there is a need in the art for a system that minimizes particle generation in liquids during filling the containers, transporting the filled containers, and dispensing the liquids from the containers.